The present invention relates to compositions and processes useful for inhibiting the transfer from one fabric to another of dye released into laundering solution from colored fabrics during conventional laundering of such colored fabrics. The compositions and processes utilize in their broadest aspect a peroxygen compound, an activator compound having particular peroxygen activation effects, a zwitterionic surfactant, and a buffer compound.
One of the most persistent and troublesome problems arising during modern fabric laundering operations is the tendency of some colored fabrics to release into laundering solutions dye which is then transferred during laundering onto other fabrics being washed therewith. Heretofore, there has been no good way to combat the problem of dye transfer other than by mechanically sorting the fabrics to partition said fabrics into dark and light shades for separate laundering.
Much of the difficulty in reducing dye transfer stems from the fact that many different types of dyes are utilized to color many different types of fabrics. Common fabric dyes include direct dyes used primarily to color cotton and rayon fabrics, acid dyes used primarily on nylon fabrics, disperse dyes used primarily on polyester/cotton, polyester, nylon, and Spandex fabrics, azo dyes used primarily on cotton and nylon fabrics, and vat dyes used primarily on cotton and rayon fabrics. Direct, acid and disperse dyes are in general readily released into washing solution while azo and vat dyed fabrics bleed very little. Cotton, nylon, rayon and Spandex fabrics have a strong propensity to pick up from solution solubilized or suspended dyes while polyester/cotton and polyester fabrics pick up such dyes to a lesser extent.
Suspended or solubilized dyes of all types can to some degree be oxidized in solution by employing known chlorine, peroxygen, activated peroxygen or peroxygen-chlorine bleaching compositions in high concentrations. While such bleaches inhibit dye transfer, they also damage dyes on fabrics thereby making their use for laundering of colored fabrics undesirable. Some of the milder peroxygen and activated peroxygen bleaching formulations can be utilized during laundering of colored fabrics with minimal color damage. (Examples of such compositions are the ketone-activated peroxygen bleaching compositions disclosed in the copending U.S. patent application of Ronald E. Montgomery, Ser. No. 393,262, filed Sept. 28, 1972, now U.S. Pat. No. 3,822,114.) While compositions of these latter two types are effective for direct bleaching of fabrics and do to some extent eliminate transfer of certain solubilized or suspended dyes, there are in the average colored wash load inevitably some of the many kinds of dyes and fabrics against which such compositions are not effective for dye transfer inhibition.
Accordingly, it is an object of the present invention to provide compositions which can be added to fabric laundering solutions to eliminate the transfer of most solubilized or suspended dye from one fabric to another during washing no matter which types of dyes and fabrics are present.
It is a further object of the instant invention to provide compositions which accomplish effective dye transfer inhibition without damaging dyes on the fabrics themselves.
It is a further object of the present invention to provide dye transfer inhibition compositions which are compatible with and in fact can be made a part of conventional surfactant-containing fabric laundering detergent compositions.
It is a further object of this invention to provide a process useful for inhibiting dye transfer among fabrics in a laundering solution.
It has been discovered that by combining certain peroxygen compounds with certain activator compounds, with a zwitterionic surfactant, and with buffer compounds, compositions and processes can be realized which accomplish the above objectives and provide useful dye transfer inhibition heretofore unavailable for colored fabric laundering operations.